Pathology + clinical of UTI Flashcards
Classic symptoms (4) /signs (2) of a lower UTI
Dysuria (pain on peeing)
Polyuria
Frequency (means increased frequency)
Urgency
Haematuria
Suprapubic tenderness
All of urinary tract is sterile apart from the
terminal urethra
Terminal urethra is not sterile compared to rest of urinary tract as it’s covered in what
skin and gut flora
When collecting urine specimen for culture, why is mid stream urine collected instead of initial urine
because initial void of urine gets heavily contaminated with flora as it exits the terminal urethra
Mid stream urine will contain less flora; will still be present as flora is always present but diminished
In an MSSU (mid stream specimen urine) culture, a bacterial growth of 10^5 per ml indicates
infection
In an MSSU (mid stream specimen urine) culture, a bacterial growth of <10^3 per ml indicates
no infection
UTIs include the following, define each:
Cystitis Bacteriuria Pyuria Sterile pyuria Acute pyelonephritis Chronic pyelonephritis
Cystitis - inflammation of bladder
Bacteriuria - bacteria in urine
Pyuria - large amount of pus cells in urine
Sterile pyuria - urine is negative on culture but significant numbers of pus cells are present
Acute pyelonephritis - kidney infection
Chronic pyelonephritis - renal scarring and potentially loss of renal function due to recurrent acute pyelonephritis
How may UTI present in infants (3)
Fever
Malaise
Failure to thrive/poor feeding
How many UTI present in the very old (2)
Incontinence
Immobile
How should women presenting with 3 or more of the classic UTI symptoms (Dysuria, Polyuria, Frequency,
Urgency) or with particularly severe symptoms, be treated
should be treated empirically with antibiotics without further investigation.
-3 day course
On dipstick testing, the presence of the following 4 things usually indicates UTI:
Nitrite
Protein
Leukocytes
Blood
Causative organisms of UTI in community and hospital (6)
More in community:
E. coli
Staph. saprophyticus
More in hospital: Proteus sp. Enterococcus faecalis Klebsiella sp. Pseudomonas sp.
Most common UTI causative organism
E. coli
Women presenting with 3 of the classic UTI symptoms or more severe are just treated empirically with antibiotics without investigation, however women presenting with 2 classic symptoms or less are managed differently; how?
MSSU
Predisposing factors of UTI (6)
Stasis of urine, e.g. in pregnancy
Anatomical abnormality of UT, e.g. duplicated ureter, vesico-ureteric reflux
Renal cysts
Calculi in the urinary tract
Immunosuppression, e.g. long term steroids, DM
Foreign body, e.g. catheter
Stasis of urine is a predisposing factor to a UTI, what are some causes of stasis of urine (2)
Obstruction of the UT
Spinal cord/brain injury - causes loss of feeling of a full bladder
Immunosuppression predisposes to UTIs - what kind of people does this include
Diabetics
On chemo
Long term corticosteroids
Describe how an obstruction at the level of the urethra can cause kidney swelling
Urine backflow –> urethral and bladder dilation –> bilateral ureter dilation –> bilateral hydronephrosis (swelling of kidneys due to build up of urine)
Describe how obstruction at the level of the renal pelvis can cause hydronephrosis
Unilateral dilation of ureter –> unilateral hydronephrosis
Describe 2 ways an obstruction in the urinary tract can predispose to UTI
Slows urine flow so can’t flush bacteria out –> infection
Slows urine flow –> sediments form –> calculi formation –> obstruction –> more dilation and infection
What is the triad of the consequences of obstruction in the urinary tract
Obstruction –> infection –> calculi –> obstruction again –> more infection etc
Name some congenital urinary tract abnormalities/obstructions
Vesicle-ureteric (bladder-ureter) reflux
Congenital pelvi-ureteric junction obstruction
What is vesico-ureteric reflux
Congenital problem where urine back flows from bladder into kidneys because the normal constriction of the ureter as it enters the bladder wall is lost, allowing urine to reflux
Common causes of urinary tract obstruction
- men
- women
- both
Benign prostatic hyperplasia (BPH)
Uterine prolapse
Tumours
How does a spinal cord/brain injury cause stasis of urine
Decreased sensation of when to micturate as can’t sense when bladder is full
When eventually micturating, not emptied completely so high residual volume of urine in bladder –> stasis of urine
Predisposing factors to UTI specific to females (5)
Short urethra
Closeness of urethra to rectum
Lack of bacteriostatic prostatic secretion
Sexual activity
Pregnancy - pressure on ureters and bladder
60 year old women who presents with UTI symptoms who hasn’t had something like this since 25 - what would you be suspicious of
uterine prolapse
Acute complication of UTI
Sepsis
Chronic complications of UTI
Chronic pyelonephritis –> hypertension, renal failure
The following are features of acute urinary retention except:
a. painful
b. palpable bladder
c. inability to urinate
d. bladder volume >800ml
e. percussible bladder
d
The following organisms are commonly associated with urinary tract infections except:
a. E. coli
b. Klebsiella species
c. Proteus species
d. Chlamydia trachomatis
e. Pseudomonas aeruginosa
d
Clinical features of acute pyelonephritis (6)
Fever
Flank pain/ costovertebral angle tenderness
Nausea/vomiting
Dysuria/frequency - LESS
Clinical features of UTI in children
Fever Irritability Poor feeding Dysuria Frequency Abdo/flank pain
1st line investigation of UTI + other investigations
Urine dipstick - for blood, nitrites, proteins, leukocytes
Urine microscopy
Urine culture + sensitivity
Imaging investigations of UTI in children/men/recurrent UTIs (not for uncomplicated UTIs in women) (2)
USS
CT of renal tract
In uncomplicated UTIs, urine dipstick is usually enough evidence to give antibiotics empirically but what LAB investigations should be done in complicated UTIs to confirm diagnosis (2)
Urine CULTURE + sensitivity - to see what antibiotics to use
Urine microscopy
Treatment of uncomplicated UTI in females
Empirical - 3 days of trimethoprim or nitrofurantoin
Which antibiotic that treats uncomplicated UTIs in females is not recommended in pregnant females
Trimethoprim
Which UTI causative organisms are more often found in hospital patients, often associated with catheters or instrumentation of the urinary tract (3)
They tend to be more antibiotic resistant
Proteus, Klebsiella and Pseudomonas sp
Treatment of complicated UTI in females
- outpatient (2)
- inpatient (if severe) (1)
Outpatient
- 7 days ciprofloxacin
- Nitrofurantoin if pregnant
Inpatient
-If severe, may need IV gentamicin or ceftriaxone
Treatment of acute pyelonephritis
-empirical (2 options)
Antibiotic chosen should be based on culture sensitivity results
Empirical antibiotics include:
- ciprofloxacin (a fluoroquinolone)
- or cefixime (a cephalosporin)
Describe the various tests which may be performed on urine and explain the significance of the results in relation to infection (3)
Urine dipstick - likely infection if there’s proteins, blood, nitrites, leukocytes
Urine microscopy - can do gram stain which will stain the bacteria (typically gram -ve rods, e.g. E. coli)
Urine culture + sensitivity - culture may show lots of bacteria colony forming units
What is pyelonephritis + pathophysiology of acute pyelonephritis
Infectious inflammatory disease of the renal parenchyma, calices, and pelvis
Usually due to gut bacteria that ascend up the urinary tract to kidneys or spread via blood to kidneys
Investigations of acute pyelonephritis (6)
-bloods
Urinalysis - dipstick, Urine microscopy + gram stain Urine culture + sensitivity FBC - shows leukocytes CRP Blood culture
Preferred antibiotic of use for UTIs in pregnancy
Nitrofurantoin
Catheter related UTI shouldn’t automatically be treated because catheters become colonised with mixed organisms and a positive culture is not an indication for treatment
But what would indicate treatment for these patients
symptomatic (e.g. feverish, suprapubic pain)
and/or shows signs of infection (e.g. pyrexial, tachycardic, pyuria in urine specimen)
Patients suffering from recurrent episodes
of UTI require careful history taking and examination to establish whether there are any risk factors which can be reversed.
General management principles for these patients with recurrent UTIs (4)
Drinking lots of fluids (≥1.5L/day),
Emptying the bladder after sexual intercourse
Void every 2-3 hours
Long term antibiotic prophylaxis, with one tablet of nitrofurantoin or trimethoprim per night for up to one year, may be successful if no predisposing factors found
What is asymptomatic bacteruria
Presence of bacteria (>10^5 colony forming units/ml urine) in urine but no symptoms/signs
UTI in children should be followed up to identify if they have what
Vesicle-ureteric reflux as this can lead to renal scarring if untreated
Methods of urine collection (3)
+ methods of transportation to the lab (2)
- MSSU
- Catheter specimen if catheterised - from the port, NOT the collection bag
- Clean catch urine - in children
Collected into a sterile vessel that is kept refrigerated
OR
Collected into a special container containing boric acid to prevent bacterial overgrowth
What is reflux nephropathy
Damage/eventual scarring of the kidneys due to back flow of urine, usually due to vesico-ureteric reflux
Most common cause of chronic pyelonephritis
+ may or may not lead to
Chronic vesico-ureteric reflux
End stage renal disease
Patients with chronic pyelonophritis may have a history of (3)
Vesicoureteric reflux
Acute pyelonephritis
Urinary tract obstruction, e.g. congenital/anatomical abnormalities, BPH, calculi
Sterile pyuria and negative urine cultures suggest urinary tract infection by the bacteria … or …
Neisseria gonorrhoeae or Chlamydia trachomatis.
